1. Field of the Invention
This invention relates to apertured nonwoven fabrics made of hydraulically entangled polyester staple fibers. In particular, the invention concerns such fabrics of improved disentanglement resistance in which the fibers have a particular ribbon-shaped cross-section.
2. Description of the Prior Art
Nonwoven fabrics in which hydraulically entangled, staple fibers form a strong, apertured structure, without the presence of resin binder or fiber-to-fiber melt bonds, are known in the art. For example, U.S. Pat. No. 3,485,706 broadly discloses that apertured nonwoven fabrics can be made by hydraulic entanglement techniques from a wide variety of fibers of different cross-sections, denier, length, composition, etc. More recent disclosures of preferred methods of making such fabrics are found in U.S. Pat. No. 4,069,563. Commercial fabrics of this type made from polyester fibers of circular cross-section are disclosed in Du Pont Technical Information Bulletin SN-1, "Properties and Processing Sontara.RTM. Spunlaced Fabrics of 100% Polyester Fiber," June 1979. Although such nonwoven fabrics have found application in a wide variety of products, increased disentanglement resistance would enhance their utility and versatility of the fabrics. The importance of disentanglement resistance to the surface stability, strength, washability, etc. of spunlaced fabrics is disclosed in M. M. Johns & L. A. Auspos "The Measurement of the Resistance to Disentanglement of Spunlaced Fabrics," Symposium Papers, Technical Symposium, Nonwoven Technology--Its Impact on the 80's, INDA, New Orleans, Louisiana, 158--174 (March 1979). The purpose of this invention is to provide such spunlaced fabrics with improved resistance to disentanglement.